Spot and flood lights for outdoor applications have traditionally used sodium vapor lamps or mercury vapor lamps. Halogen lamps and incandescent lamps have also been used, despite higher energy cost, because of lower initial cost. However, LED spot and flood lights are becoming increasingly popular because of their higher overall luminous efficiency, which is typically comparable to or better than sodium vapor lamps and generally much better than mercury vapor lamps and incandescent lamps. LED lamps for spot light and flood light applications generally have a service life that can be 10 to 50 times longer than conventional incandescent lamps and sodium vapor lamps, and typically somewhat longer than mercury vapor lamps. LED spot and flood lamps can generally provide lower overall costs (total energy, initial, replacement and maintenance costs) than the alternatives, especially for high use applications, such as streets, parking lots, walls, landscapes and billboards.
Conventional LED floodlights and spot lights generally comprise a plurality of LEDs arranged in an array or other pattern behind a clear panel or a diffuser. A disadvantage of such designs is that they do not provide a well-defined illumination pattern of relatively uniform intensity and color.